1. Field of the Invention
The present invention relates to a motor using a kinetic pressure bearing, and more particularly to a sealing structure for a motor using a kinetic pressure bearing, capable of improving quality and productivity by more completely preventing an oil provided for kinetic pressure generation and lubrication, from leaking out.
2. Description of the Related Art
In general, a small precision motor currently used, adopts a fluid kinetic pressure bearing for generating kinetic pressure by torque due to rotation of a motor in the inside of a bearing so that a rotor floats above a stator and rotates, and for heat-resisting and abrasion-resisting properties.
FIG. 1 is a cross-sectional view of a motor using a kinetic pressure bearing of the related art, and FIG. 2 is an exploded, cross-sectional view of a sealing structure for a motor using a kinetic pressure bearing of the related art.
The motor of the related art, consists of: a cylinder shaped bearing 104 fixed on a base plate 102; a stator 106 fixed on the outer peripheral surface of the bearing 104, and to which power supply is applied; a magnet 108 arranged, with a constant interval, above the outer peripheral surface of the stator 106, for being rotated by interaction with the stator 106; a rotor 110 on which the magnet 108 is fixed and positioned on the upper side of the bearing; a shaft 112 inserted into the bearing 104 and fixed on the rotor 110 in its upper end, for supporting the rotor 110 so that the rotor is rotatable, and for generating kinetic pressure while being rotated in the interior of the bearing 104; a sealing unit 120 mounted on the lower end of the bearing, for preventing an oil provided to the interior of the bearing 104, from leaking out.
The sealing unit 120 is fixed on the lower end of the bearing 104 by caulking process, and consists of: a cover plate 114 having an air exhausting hole 116 for discharging an air of the interior of the bearing 104, to the outside; a bending member 118 adhered to the back side of the cover plate 114, for preventing leakage of an oil by sealing the air exhausting hole 116.
Assembling process for the sealing unit of the related art having the foregoing construction, will be descried with reference to FIG. 2.
A cover plate 114 is fit into the bearing 104 and fixed by caulking process. After sufficient amount of oil is provided to the interior of the bearing 104, a shaft 112 fixed on the rotor 110 is inserted into the interior of the bearing 104. At the moment, oil except the oil necessary for lubrication and kinetic pressure generation in the interior of the bearing 104, is exhausted together with the air in the interior of the bearing 104, to the outside through the air exhausting hole 116.
After that, the oil exhausted through the air exhausting hole 116 and stuck on the cover plate 114, is wiped away, and the bending member 118 is processed by heat fusion in order to seal the air exhausting hole 116, so that leakage of the oil in the interior of the bearing 104 to the outside, is prevented and at the same time, inflow of external air is prevented.
But, in the sealing structure for the motor using the kinetic pressure bearing of the related art as descried above, as the air exhausting hole remains exposed to the outside, there may exist a danger of incomplete hardening of the bending member due to mixture of the oil and the bending member upon heat fusion of the bending member. Additionally, due to such incomplete hardening, problems that adhesive force of the bending member is deteriorated and the oil in the interior of the bearing leaks out to the outside, or external air penetrates into the interior of the bearing, seriously spoiling the bearing, deteriorating performance of the motor, are generated.
Also, a problem that the bending member flows into the interior of the bearing through the air exhausting hole, upon heat fusion of the bending member, and is mixed with the oil, deteriorating lubrication performance, thereby shorting life of the motor due to abrasion, is generated.
To solve the above-indicated problems, it is, therefore, an object of the present invention to provide a sealing structure for a motor using a kinetic pressure bearing, capable of improving productivity through reduction in assembling time by modifying a sealing structure of a bearing, and of improving life and performance of a motor by more effectively preventing oil in the interior of the bearing from leaking out to the outside.
The foregoing and other objects and advantages are realized by providing a sealing structure for a motor using a kinetic pressure bearing including: a bearing fixed on a base plate; a stator arranged on an outer peripheral surface of the bearing; a rotor arranged, with constant interval, on an outer peripheral surface of the stator; a shaft inserted into the bearing, and fixed in the rotor; a cover plate fixed on a lower end of the bearing, and having an air exhausting hole for discharging an air in an interior of the bearing to an outside; a first plate fit into a back side of the cover plate, for sealing the air exhausting hole; a packing member stuck on a back side of the first plate, for preventing leakage of an oil; a second plate fixed on a back side of the packing member, for protecting the packing member.
It is a preferable aspect of the present invention that a sealing is fit between a back side of the bearing and the cover plate, for preventing oil from leaking out to a gap between the bearing and the cover plate.
It is another preferable aspect of the present invention that the cover plate has a fitting portion so that the first plate, the packing member and the second plate are sequentially fit, respectively, in a back side of a cylindrical shape.
It is yet another preferable aspect of the present invention that the fitting portion is of a cylindrical shape having a predetermined length and is fixed by heat fusion after the first plate, the packing member and the second plate are fitted.
It is another preferable aspect of the present invention that the cover plate is manufactured by metal or synthetic resin.
It is another preferable aspect of the present invention that the first and the second plates are manufactured in form of a cylindrical shape having a predetermined thickness and made of metal or synthetic member.
It is another preferable aspect of the present invention that the packing member is manufactured by rubber material having a predetermined elasticity.